2 girls 1 monkey

Summer has finally come in full force with outdoor temps in the mid 30s. I went away for a day and had to close the windows for security reasons and my growroom hit 35c/95f that night. Ive switched to vitalink nutes as the grow shop was out of stock of canna, They seem similar enough, started out at 2.5ml of each A+B and it came to 1.4ec but it was climbing quickly so I topped up with water to 1.2ec. Dropped the CalMag as the vitalink has plenty already. A couple of the tallest colas that are out in the open are curling up slightly as you can see in the GG4 photo, as this is only a tiny percentage of the overall plant I'm not going to go to drastic measures to try and fix it. The GSC #2 cut is in the bottom left corner, it's about half the size of the other 3 plants as it grew much slower during veg, you can see in the first photo of the canaopy it barely grew through the 2nd trelis. It just looks like a typical skunk cross at this point, though the healthiest plant in there for sure. The GSC #1 cuts are struggling. The leaf tips are noticably burnt as well as brown patches on the leaves. The new sugar leaves look like basil and very few trichomes on the bud. It looks like it's wanting to throw out of bunch of fox tails any minute too. I don't know if its because it's a particularly fussy strain that requires tighter growing parameters or if theres something else more significant. My best guess is low oxygen in the nutrients. Ive read on forums that with this style of NFT trays once plants get to a certain size the first plants use all the oxygen and starve the plants further down. Until now Ive had the pump restricted because it was noisy but ive removed that as well as added a second pump to agitate the tank for more overall dissolved oxygen. Hopefully this will improve things.